U.S. patent number 4,927,546 [Application Number 07/276,728] was granted by the patent office on 1990-05-22 for method for inhibiting growth of algae in recreational water.
This patent grant is currently assigned to PPG Industries, Inc.. Invention is credited to Edward J. Sare, Charles R. Wiedrich.
United States Patent |
4,927,546 |
Wiedrich , et al. |
May 22, 1990 |
Method for inhibiting growth of algae in recreational water
Abstract
Recreational water, e.g., swimming pools, as opposed to
industrial water, containing a source of free available halogen,
e.g., chlorine, is treated with amounts of a 2-oxazolidinone, e.g.,
4,4-dimethyl-2-oxazolidinone to thereby inhibit the growth of algae
during the absence of biocidal amounts of free available
halogen.
Inventors: |
Wiedrich; Charles R.
(Wadsworth, OH), Sare; Edward J. (Berkeley Heights, NJ) |
Assignee: |
PPG Industries, Inc.
(Pittsburgh, PA)
|
Family
ID: |
25673890 |
Appl.
No.: |
07/276,728 |
Filed: |
November 28, 1988 |
Current U.S.
Class: |
210/755; 210/756;
210/764 |
Current CPC
Class: |
C02F
1/50 (20130101); C02F 1/76 (20130101); C02F
2103/42 (20130101) |
Current International
Class: |
C02F
1/50 (20060101); C02F 1/76 (20060101); C02F
001/76 () |
Field of
Search: |
;210/755,764,765,756
;422/37 ;514/376 ;424/661 ;71/67 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"A Novel Chloramine Compound for Water Disinfection", H. D. Burkett
et al, Water Resources Bulletin, vol. 17, No. 5, pp. 874-879, Oct.
1981. .
"Potential New Water Disinfectants", S. D. Worley et al, Water
Chlorination: Environmental Impact and Health Effects, vol. 5, Ch.
98 (1985). .
"Comparisons of a New N-Chloramine Compound with Free Chlorine as
Disinfectants for Water", S. D. Worley et al, Progress in Chemical
Disinfection, Proceedings of the Second Biannual Conference, pp.
45-60 (1984). .
"New Antimicrobial Agents for Treatment of Water", S. D. Worley et
al, NTIS, Report WO55507 (PB82-168535), Nov. 30, 1981..
|
Primary Examiner: Hruskoci; Peter
Attorney, Agent or Firm: Stein; Irwin M.
Claims
We claim:
1. A method for inhibiting the growth of algae in a stored body of
water in the absence of algicidal amounts of free available
halogen, which comprises providing in said body of water from about
0.05 to 4.5 ppm of a 2-oxazolidinone and a sufficient amount of a
source of halogen to provide from about 0.03 to about 2.8 ppm
respectively of combined available halogen based on the
corresponding halogen-containing, 2-oxazolidinone, said halogen
being selected from the group consisting of chlorine and bromine,
said 2-oxazolidinone being represented by the graphic formula:
##STR2## wherein R.sub.1 is a C.sub.1 -C.sub.4 alkyl; R.sub.2 is
selected from the group consisting of C.sub.1 -C.sub.4 alkyl,
hydroxy, hydroxymethyl, C.sub.1 -C.sub.4 alkoxy and --Ph--R,
wherein Ph is phenylene and R is selected from the group consisting
of C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy and hydroxy.
2. The method of claim 1 wherein R.sub.1 and R.sub.2 are each a
C.sub.1 -C.sub.4 alkyl, and the halogen is chlorine.
3. The method of claim 2 wherein R.sub.1 and R.sub.2 are each
methyl.
4. The method of claim 3 wherein the amount of 2-oxazolidinone
provided in said body of water is from about 2 to about 4 ppm, and
the amount of combined available chlorine provided by the
chlorine-containing 2-oxazolidinone is respectively from about 1.2
to about 2.5 ppm.
5. The method of claim 3 wherein the body of water is a swimming
pool or hot tub.
6. A method for inhibiting the growth of algae in a stored body of
recreational water selected from the group consisting of swimming
pools and hot tubs in the absence of biocidal amounts of free
available chlorine, which comprises introducing into said body of
water from about 0.05 to 4.5 ppm of a 2-oxazolidinone and a source
of chlorine in amounts sufficient to provide from about 0.03 to
about 2.8 ppm respectively of combined available chlorine, based on
the corresponding chlorine-containing 2-oxazolidinone, said
combined available chlorine being present in amounts sufficient to
be algistatic but insufficient to be algicidal, said
2-oxazolidinone being represented by the graphic formula: ##STR3##
wherein R.sub.1 and R.sub.2 are each a C.sub.1 -C.sub.4 alkyl.
7. The method of claim 6 wherein R.sub.1 and R.sub.2 are each
methyl.
8. The method of claim 7 wherein the amount of 2-oxazolidinone
introduced into the body of water is sufficient to provide from
about 1.2 to about 2.5 ppm respectively of combined available
chlorine based on the corresponding chlorine-containing
2-oxazolidinone.
9. The method of claim 7 wherein the source of chlorine is selected
from the group consisting of chlorine, calcium hypochlorite, sodium
hypochlorite, and chloroisocyanurates.
10. A method for inhibiting the growth of algae in a stored body of
recreational water, which comprises establishing
3-chloro-4,4-dimethyl-2-oxazolidinone in said water in amounts
sufficient to provide from about 0.03 to about 2.8 ppm of combined
available chlorine, said amounts being sufficient to be algistatic
but insufficient to be algicidal.
11. The method of claim 10 wherein the body of recreational water
is a swimming pool or hot tub.
Description
DESCRIPTION OF THE INVENTION
It is common to treat stored bodies of water, e.g., recreational
water, regularly with sanitizing chemicals to eradicate
disease-carrying bacteria and algae. Chlorine and certain compounds
containing chlorine have been and continue to be the foremost
sanitizers used for disinfecting such bodies of water. Chlorine
gas, sodium hypochlorite solutions, calcium hypochlorite and
chloroisocyanurates are the most commonly used water sanitizers
that provide free available chlorine in water to be disinfected.
Bromine and certain compounds containing bromine are used similarly
but to a much lesser extent.
A drawback to the use of chemical sanitizers that provide free
available chlorine is their relatively short life when added to a
body of water containing an organic load. Therefore, it is
necessary to treat periodically such bodies of water with
sanitizing chemicals in order to eradicate deleterious amounts of
bacteria and algae in the water.
Stored bodies of recreational water, such as swimming pools, hot
tubs, spas, etc., serve as breeding grounds for various types of
algae which grow in the water and on the sides and bottom of the
vessel containing the water. Unchecked growth of algae results in
cloudy and discolored water, the development of malodors, unsightly
growth on the walls and bottom of the vessel, e.g., the pool or
tub, stubborn stains, clogging of filters, a safety hazard for
swimmers, halamine, e.g., chloroamine, formation, increased demand
for sanitizers, and a breeding ground for bacteria.
The three forms of algae commonly found in recreational bodies of
water, such as swimming pools, are fast-growing green algae,
slow-growing blue-green algae and mustard or yellow algae. Once
established in pool water, green algae is eradicated usually by
shocking the pool with massive doses of chlorine. Since green algae
remains suspended in the water, filtration of the water subsequent
to shock treatment will physically remove the algae; but such a
treatment mode can require as much as seventy-two hours before the
water is clear enough to use.
Yellow algae is more resistant to treatment because it grows on the
containment vessel wall and penetrates cracks, crevices and tile
grouting. Superchlorination (shock treatment) of the water is
conjunction with mechanical scrubbing will remove most of this form
of algae. Particularly resistant patches of yellow algae may be
removed by application of a sanitizing chemical, e.g.,
trichloroisocyanuric acid or calcium hypochlorite, directly to the
affected area. However, such methods are time consuming and
expensive.
While regular treatment of a stored body of recreational water with
biocidal amounts of sanitizing chemicals will prevent the growth of
algae and kill spores of algae carried into the water by wind and
rain, a regimen of regular chemical treatment is often interrupted
during periods of non-use, such as during periods of vacation.
Moreover, when sanitizer replenishment is neglected, algae may
begin to grow quickly.
It is desirable, therefore, to provide a composition and method
which will prevent or inhibit the growth of algae in stored
recreational bodies of water, such as swimming pools, hot tubs and
spas during those periods when treatment of the water with
biocidal, e.g., algicidal, amounts of free available halogen, e.g.,
chlorine, cannot be or are not performed.
DETAILED DESCRIPTION OF THE INVENTION
It has now been discovered that certain 2-oxazolidinone
derivatives, e.g., 4,4-di(C.sub.1 -C.sub.4)alkyl-2-oxazolidinones,
more particularly 4,4-dimethyl-2-oxazolidinone, may be added to
recreational water that contains (or is treated to contain) a
source of free available halogen, e.g., chlorine, to inhibit or
prevent the growth of algae in such water for a short period when
biocidal amounts of free available halogen, e.g., chlorine, are not
present in the water. More particularly, it has been found that
such 2-oxazolidinones may be used in amounts which are algistatic
and not algicidal in order to inhibit the growth of algae in such
bodies of water during interruption of the normal regimen of
sanitizer addition to the water.
While not intending to be bound by any particular theory, it is
contemplated that the 2-oxazolidinone charged to recreational water
combines with free available halogen, e.g., chlorine or bromine,
present in the water to form in-situ a 3-halo-2-oxazolidinone e.g.,
3-chloro-4-4-di(C.sub.1 -C.sub.4)alkyl-2-oxazolidinone, which is
relatively stable under use conditions and which will provide a
source of combined available halogen, e.g., combined available
chlorine, when the amount of free available halogen in the water is
exhausted, thereby inhibiting the growth of algae. The presence of
the 3-halo-2-oxazolidinone in the body of recreational water to
which algistatic amounts of the 2-oxazolidinone is added can be
expected to control the growth of significant quantities of algae
for a time, e.g., two to three weeks, (in the absence of an
unusually large and sudden infusion of organic load) until
sanitizer in the water is replenished.
U.S. Pat. Nos. 3,931,213, 4,000,293, and 4,659,484 describe the
preparation of 3-chloro-2-oxazolidinones and further describes
their use as bactericides. The efficiency of
3-chloro-4,4-dimethyl-2-oxazolidinone for water disinfection has
been described in a number of publications, such as, "A Novel
Chloramine Compound for Water Disinfection" by H. D. Burkett et al,
Water Resources Bulletin, Vol. 17, No. 5, pages 874-879, Oct. 1981;
"Potential New Water Disinfectants" by S. D. Worley et al, Water
Chlorination: Environmental Impact and Health Effects, Vol. 5,
Chapter 98, R. L. Jolley, Ed. (1985); "Comparisons of a New
N-Chloramine Compound with Free Chlorine as Disinfectants for
Water", by S. D. Worley et al, Progress in Chemical Disinfection,
Proceedings of the Second Biannual Conference, pp. 45-60 (1984);
and "New Antimicrobial Agents For Treatment of Water" by S. D.
Worley et al, NTIS, Report W 055507 (PB82-168535). These
publications, however, do not address the efficacy of 3-chloro-4,4
-dimethyl-2-oxazolidinone against algae in the absence of biocidal
amounts of free available chlorine.
The 2-oxazolidinones and their halogenated derivatives described
herein are relatively stable in aqueous solution under conditions,
e.g., temperature, pH, etc., generally existing in recreational
water. Small amounts, e.g., algistatic amounts, of the
2-oxazolidinones, e.g., from about 0.05 to 4.5 parts of the
2-oxazolidinone per million parts of water (ppm), are presently
considered to be sufficient to keep the water free of significant
amounts of growing algae over a period of two to three weeks under
normal conditions, i.e., in the absence of a large infusion of
organic load subsequent to the last treatment of the water with
biocidal amounts of a sanitizing chemical, e.g., chlorine or
calcium hypochlorite.
The 2-oxazolidinones that may be used in the present process may be
represented by the following graphic formula I: ##STR1## wherein
R.sub.1 is C.sub.1 -C.sub.4 alkyl, such as methyl, ethyl, propyl,
isopropyl, butyl, isobutyl and secondary butyl, and R.sub.2 is
selected from the group R.sub.1, i.e., C.sub.1 -C.sub.4 alkyl,
hydroxy, hydroxymethyl, C.sub.1 -C.sub.4 alkoxy, such as methoxy,
ethoxy, propoxy, isopropoxy and butoxy, e.g., n-butoxy, isobutoxy
and secondary butoxy, and substituted phenyl (-Ph-R), particularly
para-substituted phenyl, wherein Ph is bivalent substituted phenyl
(phenylene) and said phenyl substituent, R, is selected from the
group consisting of C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy
and hydroxy. Preferably, R.sub.1 and R.sub.2 are each a C.sub.1
-C.sub.4 alkyl and, more preferably, are C.sub.1 -C.sub.2 alkyl,
e.g., methyl and ethyl. Still more preferably, R.sub.1 and R.sub.2
are the same, and are methyl.
Examples of suitable 2-oxazolidinones that may be used in the
present method include: 4,4-dimethyl-2-oxazolidinone,
4,4-diethyl-2-oxazolidinone, 4-methyl-4-ethyl-2-oxazolidinone,
4-methyl-4-hydroxy-2-oxazolidinone,
4-methyl-4-methoxy-2-oxazolidinone,
4-methyl-4-hydroxymethyl-2-oxazolidinone, and
4-methyl-4-p-methylphenyl-2-oxazolidinone. By substitution of other
R.sub.1 and R.sub.2 substituents described herein at the 4-position
of the 2-oxazolidinone, other analogous oxazolidinone derivatives
may be named. The preferred 2-oxazolidinone is
4,4-dimethyl-2-oxazolidinone. The corresponding halogen-containing
2-oxazolidinones are named 3-chloro-(or
3-bromo-)-4,4-A-2-oxazolidinones, wherein A represents the R.sub.1
and R.sub.2 substituents, e.g.,
3-chloro-4,4-dimethyl-2-oxazolidinone.
The 2-oxazolidinones described herein may be prepared by reaction
of the corresponding alkanolamine with a di(lower alkyl) carbonate,
such as diethyl carbonate, in the presence of a strong base such as
an alkali metal alkoxide, e.g., sodium methoxide, or with phosgene.
See, for example, U.S. Pat. No. 2,399,118.
In practicing the method of the present invention, an algistatic
amount of the 2-oxazolidinone is established in a stored body of
water that contains or is treated to contain a source of halogen,
e.g., chlorine. By algistatic is meant that a sufficient amount of
the 2-oxazolidinone is introduced into the halogen-containing water
to thereby inhibit or prevent the significant growth of algae but
that such amounts are insufficient to kill the microorganism, i.e.,
the 2-oxazolidinone is not used in algicidal (biocidal) amounts.
Stated differently, an algistatic amount of the 2-oxazolidinone (in
combination with the source of halogen) will provide at least 50
percent control of an algae in a biological primary culture of the
algae for three weeks. Algistatic amounts of 2-oxazolidinone will
vary with the particular recreational body of water treated and
will depend on such parameters as water temperature, pH, and the
level of exposure of the water to sunlight. Generally, between
about 0.05 and 4.5 parts of the 2-oxazolidinone per million parts
of water (ppm), more particularly between about 2 and about 4 ppm
of 2-oxazolidinone, is added to a body of recreational water to
inhibit the growth of algae therein.
The 2-oxazolidinone compound may be charged to the body of
recreational water during, prior to, or subsequent to a regular
treatment of the water with halogen or halogen-containing
sanitizers, e.g., chlorine gas or chlorine compounds providing free
available chlorine, such as a sodium hypochlorite solution, calcium
hypochlorite and chloroisocyanurates. In one embodiment, it is
contemplated the 2-oxazolidinone may be introduced into the water
when the biocidal sanitizer is substantially deleted. In a
preferred, embodiment, the 2-oxazolidinone compound is incorporated
during normal sanitizer treatment of the body of water, e.g., when
the water is treated with biocidal amounts of sanitizer, such as a
source of free available chlorine (FAC), so that the level of
combined available chlorine from the chlorine-containing
2-oxazolidinone is from about 0.03 to about 2.8 ppm, e.g., 1.2 to
about 2.5 ppm.
Thus, the 2-oxazolidinone may be introduced into the body of water
in amounts of from about 0.05 or 0.1 to 4.5 ppm followed by a
sufficient quantity of a source of halogen to provide from about 5
to about 10 ppm, e.g., 8 to 10 ppm, of free available halogen,
e.g., chlorine. During an ensuing period when previously introduced
amounts of free available halogen have become exhausted and
sanitizer replenishment of the water is not performed, i.e.,
biocidal amounts of sanitizer are not introduced into the water and
such amounts are therefore absent, halogen, e.g., chlorine, of the
combined available halogen from the halogen-containing
2-oxazolidinone will inhibit growth of algae in the water for
periods of up to about three weeks of no maintenance (no addition
of sanitizers such as biocidal amounts of FAC). Following this
period of no maintenance, the water may be re-standardized, i.e.,
free available halogen, e.g., chlorine, or other sanitizing
chemicals are introduced into the water to their normal levels.
Standardization is typically accomplished by superchlorination of
the water to remove any organic matter, bacteria and algae that
accumulated during the period of no maintenance. Standardization
will also regenerate the halogen-containing 2-oxazolidinone,
thereby providing a continuum of a residual source of combined
available halogen.
Commonly, the temperature of recreational water will vary from
about 18.degree. C. to about 43.degree. C., the latter being
temperatures which have been described as being used in hot tubs.
The pH of recreational water will optimally range between about 7.2
and 7.6 for bather comfort and efficiency of disinfection by
chlorine (Cl.sup.+) sanitizers.
Free available chlorine (FAC) is chlorine in the form of
hypochlorous acid (HOCl) or hypochlorite ion (ClO.sup.-). The
recommended free available chlorine concentration in swimming pools
is between about 1 and about 3 ppm. In hot tubs, the recommended
free available chlorine concentration is between about 1 and about
5 ppm free available chlorine. Combined available chlorine (CAC) is
chlorine provided by chloramines, i.e., compounds containing one or
more chlorine atoms attached to a nitrogen atom.
The chlorine content of recreational, e.g., pool, water may be
determined colorimetrically using the Palin DPD test using
N,N-diethyl-p-phenylenediamine. The colorimetric test measures the
hypochlorous acid content or free available chlorine content (FAC)
and the total available chlorine (TAC) of the water. By subtracting
the free available chlorine content from the total available
chlorine, the amount of combined available chlorine (CAC) may be
calculated. Determination of CAC in water in this manner gives a
reasonably accurate reading of its chloramine content.
The present process is more particularly described in the following
examples which are intended as illustrative only since numerous
modifications and variations therein will be apparent to skilled in
the art. In order to simulate the addition of 2-oxazolidinone
derivative to a body of water treated with free available chlorine,
and the resultant effect of such addition on algae, calcium
hypochlorite was added to an aqueous solution of
4,4-dimethyl-2-oxazolidinone, and the resultant solution in various
concentrations added to an algae culture.
EXAMPLE 1
To a vessel containing 153.0 grams of an aqueous solution (18.3
percent) of 4,4-dimethyl-2-oxazolidinone were added 3822 grams of
chlorine demand free water and a total of 58.36 grams of 71.1
percent granular calcium hypochlorite. The resultant aqueous
mixture was stirred and filtered to remove a white precipitate,
which was assumed to be calcium carbonate. The aqueous mixture was
analyzed and found to contain 3950 parts combined available
chlorine (CAC) per million parts of solution (ppm) and 750 ppm of
free available chlorine (FAC). Eight days later, 37.5 milliliters
of the aqueous mixture were diluted with 250 grams of chlorine
demand free water. Analysis of this diluted solution found 360 ppm
of combined available chlorine and 0 ppm free available chlorine.
The combined available chlorine (CAC) was attributed to
3-chloro-4,4-dimethyl-2-oxazolidinone, which was presumed to have
been formed in situ. This final stock solution was again diluted
with water to obtain final concentrations of 180, 36, 3.6, and 0.36
ppm combined available chlorine.
EXAMPLE 2
Thirty milliliters of a proteose peptone culture medium was placed
into a series of test tubes (200 mm.times.50 mm) using an automatic
pipetter. The tubes were capped, steam sterilized at
121.degree..+-.2.degree. C. for twenty minutes and allowed to cool
to room temperature.
The alga, Chlorella pyrenoidosa, was transferred from a stock agar
culture into a proteose peptone medium and maintained at
22.degree..+-.2.degree. C. in an Erlenmeyer flask to establish a
stock culture of the algae. The cooled test tubes were inoculated
with alga from the flask to establish an initial cell concentration
of approximately 3.times.10.sup.5 cells per milliliter (primary
culture).
A 1.0 milliliter aliquot of the 360 ppm CAC solution of prepared in
Example 1 was charged to each of two appropriately labeled test
tubes containing the primary cultures. Two other innoculated,
oxazolidinone-untreated tubes containing primary cultures were used
as viability controls. This procedure was repeated with 1.0
milliliter aliquots of the 180, 36, 3.6 and 0.36 ppm CAC
solutions.
Following two days of incubation at 22.degree..+-.2.degree. C.,
with 16 hours of cool fluorescent light while being oscillated at
100 oscillations per minute, a 0.01 milliliter aliquot from each
test tube was aseptically transferred to a tube containing 30
milliliters of sterile proteose peptone medium. These subcultures
and the primary cultures were maintained under the aforedescribed
temperature and light conditions for three weeks. Each week, the
test tubes were visually observed and optical density measurements
taken. Results are tabulated in Table I.
TABLE I ______________________________________ A. PRIMARY CULTURE
VISUAL OBSERVATION RATINGS Active Specie (CAC) Test Weeks Conc.
(ppm) 1 2 3 ______________________________________ 0.00 1 3 3 0.01
0 3 3 0.12 0 2 2 1.2 0 1 2 5.8 0 0 0 11.6 0 0 0
______________________________________ Key 0 = No Growth 1 = Slight
Growth 2 = Moderate Growth 3 = Abundant Growth
______________________________________ B. PRIMARY CULTURES PERCENT
CONTROL* OF ALGAL GROWTH Average Weekly Optical Density
Measurements Active Specie (CAC) Week Conc. (ppm) 1 2 3 Percent, %
______________________________________ 0.00 0.15 0.45 0.49 -- 0.01
0.01 0.21 0.24 51.0 0.12 0 0.16 0.18 63.3 1.2 0 0.12 0.14 71.4 5.8
0 0 0 100.0 11.6 0 0 0 100.0 ______________________________________
*Percent Control = 100 (Average Rating for Control Tubes - Average
Rating for Treated Tubes) divided by the Average Rating for Control
Tubes. Based on Optical Density Measurements.
The data of Table I show that at combined available chlorine
concentrations of 5.8 and 11.6 ppm, no growth of the test algae
organism was observed after 3 weeks, i.e., that there was complete
control of algal growth. Such concentrations are, therefore, deemed
to be algicidal. Table I also shows that only moderate growth
(about 50 percent control) of the test algae organism was observed
after 3 weeks for a combined available chlorine concentration of
about 0.01 ppm. This and higher concentrations (but less than a
concentration of 4.5 ppm) are considered to be algistatic.
Although the present method has been described with specific
details of certain embodiments thereof, it is not intended that
such detail should be regarded as limitations upon the scope of the
invention except as and to the extent that they are included in the
accompanying claims.
* * * * *